How are sex scenes performed in live plays?

I was just curious, since actors in live plays don't have the advantage of a camera only focusing on their upper body, and I know that they don't actually have intercourse on stage. So how are sex scenes performed in live plays?|||Every play is unique and handles it differently. I have been involved in plays where it was full nude, on stage in full view, there as just no intercourse - it as all suggested. I have done other plays where the bodies were covered and they were just doing the actions. And even more plays still that were done in Silhouette.|||Well, in Spring Awakening, when it's actually right onstage (not hidden as the other person is speaking of) the girl just unbuttons her shirt and you can see stuff, but the guy just pulls his pants down a bit (you can't see anything) and they just make it look like they are actually having intercourse, but they aren't. But in that, besides the girl's chest and the guy's bottom, they are still fully clothed. That's the only play that I have seen that has a sex scene. And I think that is a bit more risque than most.|||They're usually done offstage or in silhouette. I've also seen them done under sheets or behind scrim so you can occasionally see a person posing, but it's just the actors rolling around.